In view of the modern medical technology development, the average life of human being is prolonged and the aging population is increasing year by year. All these give rise to lots of issues concerning the home care of aging people. As the time of aging people being home alone increases, if they incurs any contingent condition (e.g. tumble or prolonged sickness), their children may not be aware of that in time and such delay usually results in regrettable outcome.
So far, the countermeasure to this problem is to mount a camera in the room of aging people or in the home for the aged so as to keep track of their activities. However, in addition to blind zones, using the camera also requires additional labor to constantly watch the video images taken thereby. Such job is not only boring but also unrespectful of privacy of the aged. Nowadays, some human pose detection systems developed by using inertial sensor have been brought into play to attain the home care effect under the premise of no breach of privacy.
As to the body pose detection system based on the inertia sensor, a prior art represented by Bouten etl al. [C. V. C. Bouten, K. T. M. Koekkoek, M. Verduin, R. Kodde and J. D. Janssen, “A triaxial accelerometer and portable data processing unit for the assessment of daily physical activity”, IEEE Tans. Biomedical Engineering, vol. 44, no. 3, pp. 136-147, 1997.], develops a portable device for recording and determining user's daily activities. Bouten etl al. employ tri-axis accelerometer to measure the dynamic acceleration of human body, use the dynamic acceleration of human body to measure the energy consumed by human body, and determine pose by the energy consumption caused by different movement. Such prior art determines the movement with large energy difference by using a tri-axis accelerometer. Whereas, if determining pose completely by consumed energy, it is prone to a misjudged condition while determining movement with insignificant energy consumption difference and is unlikely to determine static pose.
Besides, another prior art represented by Tanaka etl al. [S. Tanaka, K. Motoi, M. Nogawa and K. Yamakoshi, “A new portable device for ambulatory monitoring of human posture and walking velocity using miniature accelerometers and gyroscope,” in Proc. of the 26th Annual International Conference of the IEEE EMBS, San Francisco, USA, 2004, pp. 2283-2286.], discloses a simple relationship which utilizes an accelerometer to calculate the inclination angle of each portion of human body, thereby observing poses of human body. However, such system needs to be mounted to three portions of a body so that it is not convenient to wear and the sensors thereof are difficult to be bundled with normal living utensils such as belt, shoes and so forth, making it hardly practical.
Moreover, refer to the technique addressed by Karantonis etl al. [D. M. Karantonis, M. R. Narayanan, M. Mathie, N. H. Lovell and B. G. Celler, “Implementation of a Real-Time Human Movement Classifier Using a Triaxial Accelerometer for Ambulatory Monitoring,” IEEE Trans. Information Technology in Biomedicine, vol. 10, Issue. 1, pp. 156-167, 2006.]. Such prior art combines the research results of various researchers, and the algorithm thereof is realized within a microcontroller. Although its system uses a Zigbee module to transmit the determination result of body pose, the system is not applied to a Zigbee network. In contrast, the present invention employs multiple Zigbee modules to construct a Zigbee wireless sensor network (WSN) (discussed in details later) so as to simultaneously observe the poses of multiple users, increase the detection range and upgrade the system's utility.
In addition to the above-mentioned description, few points concerning the drawbacks and the improvement of the prior arts are further summarized as follows:
(I) Many body pose recognition algorithms based on inertia sensor adopt time-domain or frequency-domain analysis. The poses that can be determined by those algorithms are quite limited. Hence, if the time-domain analysis and the frequency-domain analysis can be integrated, more poses may be determined.
(II) Many body pose recognition algorithms proposed by research have massive computation demand, making them infeasible for being directly loaded in a microcontroller on human body to execute the algorithms. Consequently, it is necessary for the sensed data to be stored first and then analyzed in an off-line manner. In that sense, real-time determination of pose is out of the question. To be more practical, a system equipped with real-time pose-recognizing capability must be developed. Furthermore, a body pose detection module for detecting poses of human body shall be featured by compact size and the feasibility to be integrated with daily living utensils so as to relieve user's inconvenience while carrying it.
(III) Almost all the related researches focusing on the pose detection of single target fail to determine multi-person poses at the same time. Whereas, there are usually more than one person requiring care at home. As a result, a future home care system shall develop to meet the goal of taking care of a plurality of people at the same time.
Meanwhile, because the current robotic technology is gradually mature, many researchers hope that a future robot may gradually step into a family, not only helping the works of human being but also playing a role for home security and care of the aged. Therefore, the present invention develops a set of multi-person pose recognition system attempting to be integrated with a robot through the system, such that a robot servicing at home could assist to take care the aged domestically. The body pose detection module carried by the aged uses sensors to sense a pose of the aged. Through a Zigbee WSN, a robot may simultaneously watch multiple care recipients. Thus, the system is ideal for the application to multiple care recipients in the home-for-the-aged or at home. When the robot senses an accident that a care recipient falls down, the robot could immediately go to the scene, where the accident occurs, to concern and immediately issue an alarm to inform the children of the aged, thereby further securing the home security of the aged.
The first object of the present invention is to provide a multi-person pose recognition system using a Zigbee WSN, which may recognize seven types of body poses of human namely fall down, stand, sit, lie down, go upstairs, go downstairs and walk.
The second object of the present invention is to provide a body pose detection module for realizing the pose detection algorithm, which constitutes a Zigbee WSN with a development board (CC2420DBK) of the Zigbee WSN so as to achieve the effect of observing multi-person poses.
The third object of the present invention is to provide a pose detection algorithm combining time-domain analysis and wavelet analysis, which could determine poses of human body (e.g. fall down, stand, sit, lie down, go upstairs, go downstairs, walk, etc.) by analyzing the readouts of a tri-axis accelerometer of the body pose detection module.